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21.
M K Parida Nita Sinha B Adhikary B Allanach A Alok K S Babu B Brahmachari D Choudhury E J Chun P K Das A Ghosal D Hitlin W S Hou S Kumar H N Li E Ma S K Majee G Majumdar B Mishra G Mohanty S Nandi H Pas M K Parida S D Rindani J P Saha N Sahu Y Sakai S Sen C Sharma C D Sharma S Shalgar N N Singh S Uma Sankar N Sinha R Sinha F Simonetto R Srikanth R Vaidya 《Pramana》2006,67(5):849-860
This is the report of flavor physics and model building working group at WHEPP-9. While activites in flavor physics have been
mainly focused on B-physics, those in model building have been primarily devoted to neutrino physics. We present summary of working group discussions
carried out during the workshop in the above fields, and also briefly review the progress made in some projects subsequently. 相似文献
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In spite of large spin coherence length in graphene due to small spin–orbit coupling, the created potential barrier and antiferromagnetic coupling at graphene/transition metal (TM) contacts strongly reduce the spin transport behavior in graphene. Keeping these critical issues in mind in the present work, ferromagnetic (Co, Ni) nanosheets are grown on graphene surface to elucidate the nature of interaction at the graphene/ferromagnetic interface to improve the spin transistor characteristics. Temperature dependent magnetoconductance shows unusual behavior exhibiting giant enhancement in magnetoconductance with increasing temperature. A model based on spin–orbit coupling operated at the graphene/TM interface is proposed to explain this anomalous result. We believe that the device performance can be improved remarkably tuning the spin–orbit coupling at the interface of graphene based spin transistor. (© 2015 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim) 相似文献
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Metamaterial absorbers have attracted considerable attention for applications in the terahertz range. In this Letter, we report the design, fabrication, and characterization of a terahertz dual band metamaterial absorber that shows two distinct absorption peaks with high absorption. By manipulating the periodic patterned structures as well as the dielectric layer thickness of the metal-dielectric-metal structure, significantly high absorption can be obtained at specific resonance frequencies. Finite-difference time-domain modeling is used to design the structure of the absorber. The fabricated devices have been characterized using a Fourier transform IR spectrometer. The experimental results show two distinct absorption peaks at 2.7 and 5.2?THz, which are in good agreement with the simulation. The absorption magnitudes at 2.7 and 5.2?THz are 0.68 and 0.74, respectively. 相似文献
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In this paper, reflectivity of a Distributed Bragg Reflector (DBR) has been computed by considering the effects of changes of wavelength on the changes of the refractive index of the materials of DBR layers. The intrinsic losses of the materials have been included in the computation of the reflectivity of the DBR. It has been found that the effect of change of the wavelength on the refractive index of the DBR materials reduces the Full Width Half Maxima (FWHM) of the stop band significantly which is expected to improve the laser characteristics. If the FWHM is reduced, the thickness of the active layer of a VCSEL can also be reduced which will further reduce the threshold current of the device. It has been found that the intrinsic losses of the materials have a significant effect on the reflectivity of a DBR. It has also been found that peak reflectivity of a 20 pair AlAs/GaAs DBR reduces by 0.2% after including the intrinsic losses (with a value of the intrinsic losses α = 10 cm?1). 相似文献
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A. Saha A. Ray S. Mukhopadhyay P.K. Datta P.K. Dutta S.M. Saltiel 《Applied physics. B, Lasers and optics》2007,87(3):431-436
An all-solid-state, side diode array pulse pumped Nd:YAG laser tunable for six wavelengths ranging from 1318.8 nm to 1356.0 nm
is developed. The tunability is obtained by using a grating in Littrow mode that also serves as an output coupler. The configuration
ensures a line width as low as 0.04 nm. Thermal effects limit the maximum average power to 250 mW for an average absorbed
pump power of 8.0 W in the free-running condition. An acousto-optic Q-switching of the laser provides pulses of width 251 ns
with peak power of 733 W for an average pump power of 11.5 W. The laser may find application in microsurgery and dermatology.
PACS 42.55.Xi; 42.60.-v; 42.60.Fc; 42.60.Gd; 42.62.Be 相似文献
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U. V. Valiev J. B. Gruber D. K. Sardar B. Zandi I. S. Kachur A. K. Mukhammadiev V. G. Piryatinskaya V. Yu. Sokolov I. S. Edelman 《Physics of the Solid State》2007,49(1):91-98
The Zeeman effect in the 7 F 6 → 5 D 4 absorption band of the Tb3+ ion in the paramagnetic garnets Tb3Ga5O12 and Tb3Al5O12 was studied. The field dependences of the Zeeman splitting of some absorption lines are found to exhibit unusual behavior: as the magnetic field increases, the band splitting decreases rather than increases. Symmetry analysis relates these lines to 4f → 4f electron transitions of the doublet-quasi-doublet or quasi-doublet-doublet type, for which the field dependences of the splitting differ radically from the well-known field dependences of the Zeeman splitting for quasi-doublet-quasi-doublet or quasi-doublet-singlet transitions in a longitudinal magnetic field. 相似文献
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